1. Field of the Invention
The present invention relates to a microactuator using growth and destruction of bubbles that is broadly applicable to micro-size systems and actuators, and more particularly to a microactuator using growth and destruction of bubbles which ensures rapid response of a moving member by allowing change of internal pressure according to growth and destruction of bubbles at the interface of a cavity, enables production of high power output through high internal pressure through a simple structure, and enables precise control of the moving member through adjustment of the internal pressure of the chamber and the speed of a working fluid filling the chamber according to the size and rate of growth of bubbles.
2. Description of the Related Art
In general, microminiaturized actuators can be used in micro-devices and in fields requiring high precision control. These microminiaturized actuators are drawing attention in many fields including biotechnology, medicine, war, environmental technology, and chemical processes.
When miniaturized, devices can not only operate precisely and overcome spatial constraints, but also can be applied to micro-robots for medical and military use. Accordingly, designing of microminiaturized systems have been attempted for decades.
Such microminiaturized devices have a size reduced to millimeter scale or below. Development of microelectromechanical systems (MEMS) has enabled realization of such microsystems. Nowadays, MEMS manufacturing technology is used in commercial manufacture and research into compact sensor modules, compact test devices, medical machines, high precision machines, high-tech military equipment, and inkjet printer heads.
Many microdevices require use of an actuator for supply of driving power. Each actuator provides certain magnitudes of displacement, force, and frequency. Types of driving force for the actuator include electrostatic force, piezoelectric power, thermal energy, and magnetic force.
TABLE 1TypeForceDisplacementFrequencyConstraintElectrostaticWeakLarge orLargeWeak forceforceSmallPiezoelectricStrong orLarge orLargeDevicepowerWeakSmallThermalStrongLargeSmallLowenergyfrequencyMagneticWeakSmallLarge orWeak forceforceSmall
As shown in Table 1, actuators using electrostatic force and magnetic force actuators produce relatively weak power. As to actuators using piezoelectric power, piezoelectric materials are not well suited to MEMS manufacturing technology. Actuators using thermal energy provide strong force and large displacement. However, due to slow thermal diffusion, they have a relatively low frequency on the order of hundreds of hertz.
Particularly, a representative device of an actuator using thermal energy is an inkjet head. The inkjet head produces bubbles by heating a liquid introduced into a small chamber using a heating plate and uses the produced bubbles as driving force to spray liquid droplets onto the surface of a sheet of paper through a nozzle, performing the printing operation.
Actuators utilizing thermal energy are advantageous in that they produce large force and displacement and are easy to manufacture. However, their low frequency related to heat dissipation is recognized as disadvantageous.